Process of making alpha-ionone.



PATENT OFFICE.

PHILIPPE OHUIT AND FRI' IZ BACHOFEN, OF GENEVA, SWITZERLAND,

ASSIGNORS TO CHUIT, NAEF FIRM.

82; CO, OF GENEVA, SWITZERLAND, A

PROCESS OF MAKING ALPHA-lONO N E.

SPECIFICATION forming part of Letters Patent No. 702,126, dated. June 10, 1902.

Application filed September 1901- Serial No. 761552. specimensd To all whom it may concerm.

Be it known thatwe, PHILIPPE CHUIT and FRITZ BACHOFEN, residing at the Usine de la Queue dArve, Geneva, Switzerland,,have invented an Improved Process for the Prepara the presence of acetone by the action of alk aline solutions, as first shown by Tiemann,f

(Bert'chte der Deuischen Ohemz'sch. Gesellschaft, 1893, page 2,692,) a new derivative, the pseudo-ionone. This same pseudo-ionone can be prepared by the action of other appropriate agents on a mixture of citral and acetone. By

' the action of acids the pseudo-ionone is converted into a mixture of isomerics, alpha and beta ionones, but by all hitherto known processes-the result is eithera relatively large proportion of the alpha modification with a small yield or a very incomplete conversion of the pseudo-ionone ora more favorable conversion of the latter, but a relatively large proportion of the beta modification.

According to our invention by the use of phosphoric acid,preferably in'the form of concentrated syrup, (D=1.750, say 63 Baum,) while keeping the temperature of the mixture below 0 centigrade during the process, the

vconversion will be complete and the oil obtained with an exceedingly favorable yield (eighty per cent. of the pseudo-ionone) consists chiefly of alpha-ionone.

The raw oil distilled in the steam consists of about eighty per cent. of alpha-ionone and twenty per cent. of beta-ionone and produces with para-bromphenylhydrazin, -a derivative which melts directly at 134 centigrade and after a single recrystallization in methyl al- (301101 at 142,while, furthermore,it forms with para tolylhydrazin a para tolylhydrazone, melting directly at between 123 and 126 centigrade, and after a single recrystallization in diluted methylic alcohol at 132 centigrade, whereas para-tolylhyd razone of the beta modification melts at 03 to 106 centigrade. This process therefore constitutes a very important technical improvement for the produc-' tion of ionone, and particularly of the alpha" modification thereof. Practically the same result may be obtained with the use of pyro- I phosphoric acid with a density of 1.718 at about 25 centigrade as with the phosphoric acid, with the difference, however, that by the use of the former acid therefrigerating mixture may be dispensed with and the conversion of the pseudo-ionone can be effected at ordinary temperature.

From the ionones produced in accordance with this improved process the alpha modifi-' cation thereof can be obtained in a very high- 3 state of purity,as shown exteriorly by the completely colorless appearance and its exceedingly fine odor. This can be effected. by boiling or by continuously agitatingand heating to about 100 centigrade the raw oil with a solution of bisulfite or sulfite of sodium with an addition of ammonium chlorid. The oil' is dissolved in about eight hours.

-After extracting the impurities with a suitable agent there is added to the solution, I

while still hot, a sufficient quantity of sodium chlorid to saturate it when cold, the alpha-ionone crystallized, so to speak, quantitatively in cooling, in the form. of a compound having the appearance of nacreous spangles or scales, which are then filtered off, while the beta modification under these conditions remains in the mother-lye.

The alpha-iononeaud the beta-ionone can be obtained by decomposing the crystals and the mother-lye,respectively. This constitutes avery eifec'tive and new separation of the two modifications, which differs entirely from the prior art.

When the crystallized alpha compound is decomposed by ordinary means and distilled in steam, a pure and completely colorless alpha-ionone is obtained, in whichcondition it I has not heretofore been produced. The absence of color is not momentary in the mannor of certain freshly-distilled essences, but is permanent. i

62.5 parts of syrupy phosphoric acid are cooled to a temperature of between 2 to 5 centigrade and 12.5 parts of pseudo-ionone are gradually added, the mixture being constantly agitated. After a'further agitation for about two to three hours the rather thick mixture, which now has assumed a reddishbrown color, is finally diluted with a suiticient quantity of ice and Water to form an acid of about fifty per cent. By distilling this mixture in steam about ten parts of a yellowish oil are obtained. The oil is then dissolved in the following mixture: thirty parts of bisulfite of sodium of 40 Baum, ten parts of water, 2.5 parts of a thirty-percent. solution of (-austicsoda, and three parts of ammonium chlorid by either agitating at about 100 or by boiling the whole for about eight or nine hours and then removing the impurities by means of ether, preferably by diluting it with an equal volume of water. \Vhile the solution is hot, a sufficient quantityof sodium chlorid is introduced and dissolved to completely saturate the mixture when cold. Upon the mixture being cooled all the alpha-ionone contained in the original oil is precipitated out in the form of the sodium salt 'of the hydrosullonic acid in white nacreous scales, which are then filtered off from the mother-lye. The latter should contain suificient salts to possess, a specific gravity of at. least 1.230 at twenty degrees, this being a necessary condition for obtaining the complete precipitation of all the alpha-ionone. If desired, the compound may be recrystallized by means ofhot water, in which the combination is readily soluble. The crystals are afterward decomposed by means of a solution of caustic soda or by any other known means and distilled in steam. The pure alpha-ionone thus obtained distils over with great facility with the steam. By decomposing the mother-lyes which contain beta-ionone under the form of the sodium salt of the hydrosulfonic acid the beta-ionone can be obtained as a by-product.

The separation, as shown in the art, gives by means of crystallization of the hydrosulfonic salts only an insufficient separation, as a large part of the alpha-hydrosulfonic salts remain in the mother-lye. The distillation of the beta-ionone out of the remaining solution of the two modifications is not very exact and effective, the alpha-ionone extracted out of the remaining solution not being pure. With our inventiont'. e., by adding sodium chlorid in sufficient quantity to the solution to obtain a saturated liquid when co1d-the separation is quantitative. The sodium salt of the alpha-hydrosulfouic acid which contains the alpha-ionone, the principal product of our process, is precipitated quantitatively, the sodium salt of the beta-hydrosulfonic acid remains in the mother-lye.

WVe claim as our invention 1. The herein-described process of producingalpha-ionone, consisting in reacting on pseudo-ionone with syrupy phosphoric acid at a low temperature, treating the product with a sulfite of sodium in the presence of ammonium chlorid, adding sodium chlorid and precipitating quantitatively from the thus-obtained mixture the sodium salt of the hydrosult'onic acid of the alpha-ionone, and decomposing the same by suitable methods to yield alpha-ionone in a pure and entirely colorless form, substantially as described and for the purpose specified.

2. The herein-described process of producing alpha-ionone from a mixture of cyclicisomerics consisting in treating the said mixture with a sulfite of sodium in the presence of ammonium chlorid, adding sodium chlorid and precipitating quantitatively from the thus-obtained mixture the sodium salt of the hydrosulfonic acid of the alpha-ionone, and decomposing the same by suitable methods to yield alpha-ionone in a pure and entirely colorless form, substantially as described and for the purpose specified.

In testimony that we claim the foregoing as our invention we have signed our names in presence of two subscribing witnesses.

PHILIPPE CI'IUIT. FRITZ BACHOFEN.

Witnesses:

E. IMER-SOHNEIDER,

S. H. MININER. 

